Various embodiments are directed to electrosurgical cutting and sealing instruments with jaws having a parallel closure motion that may be used, for example, in open and minimally invasive surgical environments.
Minimally invasive procedures are desirable because such procedures can reduce pain and provide relatively quick recovery times as compared to conventional open medical procedures. Many minimally invasive procedures are performed with an endoscope (including without limitation laparoscopes). Such procedures permit a physician to position, manipulate, and view medical instruments and accessories inside the patient through a small access opening in the patient's body. Laparoscopy is a term used to describe such an “endosurgical” approach using an endoscope (often a rigid laparoscope). In this type of procedure, accessory devices (such as end effectors for creating energy-induced tissue welds) are inserted into a patient through trocars placed through the body wall. Still less invasive treatments include those that are performed through insertion of an endoscope through a natural body orifice to a treatment region. Examples of this approach include, but are not limited to, cystoscopy, hysteroscopy, esophagogastroduodenoscopy, and colonoscopy.
Many of these procedures employ a flexible endoscope during the procedure. Flexible endoscopes often have a flexible, steerable articulating section near the distal end that can be controlled by the clinician by utilizing controls at the proximal end. Some flexible endoscopes are relatively small (1 mm to 3 mm in diameter), and may have no integral accessory channel (also called biopsy channels or working channels). Other flexible endoscopes, including gastroscopes and colonoscopes, have integral working channels having a diameter of about 2.0 to 3.7 mm for the purpose of introducing and removing medical devices and other accessory devices to perform diagnosis or therapy within the patient. For example, some end effectors are used to create an energy-induced weld or seal. Certain specialized endoscopes or steerable overtubes are available, such as large working channel endoscopes having a working channel of 5 mm, or larger, in diameter, which can be used to pass relatively large accessories, or to provide capability to suction large blood clots. Other specialized endoscopes include those having two or more working channels.
A common task both in minimally invasive and open surgical environments is to grasp, cut and fasten tissue while leaving the cut ends hemostatic (e.g., not bleeding). For example, it is often desirable to cut and seal bodily lumens, such as individual blood vessels or tissue including various vasculature. When sealing a fluid-carrying bodily lumen, it is often necessary for the seal to have sufficient strength to prevent leakage of the fluid, which may exert considerable fluid pressure.
Instruments exist for simultaneously making a longitudinal incision in tissue and fastening the tissue on opposing sides of the incision. Such instruments commonly include an end effector having a pair of cooperating jaw members that, if the instrument is intended for minimally invasive applications, are capable of passing through a cannula passageway or endoscopic working channel. In use, the clinician is able to close the jaw members to clamp the tissue to be cut. A reciprocating cutting instrument (or knife) is drawn distally along the jaw members to transect the clamped tissue. Simultaneously, a fastening mechanism fastens the cut ends of the tissue on opposing sides of the incision. Known fastening mechanisms include staples, sutures or various instruments utilizing energy sources. For example, various energy sources such as radio frequency (RF) sources, ultrasound sources and lasers have been developed to coagulate, seal or join together tissue volumes.